1. Field of the Invention
This invention relates to a swing arm supporting structure in a two-wheeled motorcycle.
2. Background Art
A rear wheel suspension is extensively employed in motorcycles in which a swing arm supporting the rear wheel is supported at its base end portion by a pivot bolt so as to rotate vertically. The pivot bolt is inserted into a swing arm pivot member provided on the motorcycle body. A cushion is provided between the swing arm and the body frame in order to absorb the vertical vibration of the rear wheel which is caused by uneven roads to thereby prevent the transmission of such vibration to the motorcycle body.
In the above-described rear wheel suspension, the swing arm pivot member must have a high rigidity because a variety of stress is applied thereto. Therefore, the swing arm pivot member is relatively large in thickness, with the result that the reduction in weight of the motorcycle body frame is limited to some extent.